1. Field of Invention
The present invention relates a bottle-shaped plastic container that is produced by biaxial orientation blow molding process or the like; in particular, it pertains to a container having a body that is partly recessed inwards to afford a grip region.
2. Description of Related Art
Such a bottle-shaped plastic container is disclosed, for example, in JP-4-33,238Y2 or JP-4-33,239Y2, wherein a substantially cylindrical body in its middle height region has a rear surface portion both sides of which are recessed inwards and juxtaposed to each other, to define a grip region therebetween. Such an arrangement proved to be highly advantageous in that a plastic container with an integral grip region can be produced efficiently and at a low cost, without requiring a separate grip member to be prepared in advance and subsequently connected to the body of the container.
In this type of plastic container, however, there may be instances wherein the body undergoes deformation when the grip region is grasped by hand or the inner pressure of the container increases due to an elevated temperature. An excessive deformation of the plastic container often result in overspill of the liquid content out of the container. Also, deformation of the plastic container at a location other than the grip region may degrade the appearance of the container, particularly when the deformed region is a printed surface or bears a heat shrink label or the like, indicating visual information such as trademark or the like. It is anticipated that such a problem becomes more apparent as a result of recently progressing demand for a reduced resin amount that is necessary for forming the container, or for a reduced material thickness of the container, both resulting in a reduced rigidity of the container.
It is therefore an object of the present invention to provide an improved bottle-shaped plastic container, which eliminates the above-mentioned problems of the prior art by suppressing the deformation at the ornamental front surface portion of the body portion when the grip region is grasped by hand, or the liquid content within the container is subjected to temperature change.
To this end, according to the present invention, a bottle-shaped plastic container includes a body and an opening at one end of the container that allows liquid content to be filled into the container and emptied therefrom. The body has a middle height region with front and rear surface portions, and both sides of the rear surface portion are recessed inwards and juxtaposed to each other defining a grip region therebetween. The rear surface portion of the body has a radius of curvature that is larger that a radius of curvature that is larger that a radius of curvature of the front surface portion.
With the above-mentioned arrangement of the bottle-shaped plastic container according to the present invention, the rear surface portion of the body having a relatively large radius of curvature is more liable to deform, as compared to the front surface portion, when the grip region is grasped or when the liquid content is subjected to a change in temperature. Thus, it is possible effectively to suppress an excessive deformation of the front surface portion of the body, which often forms an/ornamental portion of the container, thereby preventing the appearance of the container from undesirable degradation.
It is preferred that the radius of curvature of the rear surface portion is at least approximately 1.5 times larger than the radius of curvature of the front surface portion.
The middle height region of the body is formed with a reinforcement that extends at least partly in a circumferential direction of the body. Such an arrangement makes it readily possible to optimize the rigidity and/or strength of the container, while allowing a limited deformation of the grip region when being grasped by hand.
The reinforcement may extend in the circumferential direction of the body with a radius of curvature that is larger than the radius of curvature of the rear surface portion of the body.
The container according to the present invention may have an inner volume within a range of 1,800-4,000 cm3.
The container according to the present invention may be a so-called hot fill type container that is filled with a liquid at a temperature as high as 80-95xc2x0 C.